Preliminary Study for Strength and Freeze-Thaw Durability of Microwave- and Steam-Cured Concrete

Abstract

This study investigates the effects of steam and microwave curing on the strength development and freeze-thaw durability of concrete. Two steam-curing treatments, four microwave curing times and four types of concrete mix, were used in this study. The test results indicated that microwave heating could further increase the early strength of concrete. Pozzolanic reaction of silica fume, fly ash, and blast-furnace slag was observed to be further promoted by steam-microwave curing. Concrete samples with 10% silica fume added responded well to microwave curing. The strength gain development of concrete appeared to level off after 40 min of microwave curing. Thus, a 40-min microwave heating time appeared to be the optimal curing time. The microwave-cured concrete did not show an increase in deterioration relative to the concrete that was steam cured, but showed an increase in strength. The strength of the top layer of the steam-cured concrete blocks is lower than the strength of the middle or bottom layer.